WASHINGTON, Jan 23 (Reuters) - John Walker Lindh, the captured American al Qaeda fighter who has been charged with conspiring to kill U.S. nationals in the Afghan war, arrived in the United States on Wednesday evening to stand trial.

A U.S. official told Reuters Walker arrived at 6:05 p.m. (2305 GMT). Walker, 20, was taken by the FBI from Dulles Airport to a detention facility where he will remain in FBI custody until he appears before Magistrate Judge W. Curtis Sewell in the U.S. District Court in Alexandria, Virginia, at 9 a.m. (1400 GMT) on Thursday.

A convoy of vehicles carrying Walker could be seen on television. Flanked by two men grasping his arms, Walker, his head down, legs shackled and arms cuffed, walked slowly near the vehicles.

A senior defense official, who asked not to be identified, told Reuters that Walker -- who had been shown on television after his December arrest with long unkempt hair and a wild beard -- had asked to have his hair cut and beard shaved before he traveled back to the United States.

Walker, who goes by his mother's name, has been charged by the Justice Department with conspiring to kill Americans abroad and providing support to Osama bin Laden's al Qaeda network, which has been blamed for the Sept. 11 attacks on America.

The charges carry a maximum sentence of life imprisonment.

At the court appearance on Thursday, the Californian will be read the charges spelled out in a Jan. 15 criminal complaint and will be asked if he wants or needs an attorney.

Walker, who has not yet been formally indicted by a grand jury, will not be asked to enter a plea on Thursday.

The judge may also set a schedule for future preliminary and detention hearings.

Shortly after Walker arrived, his parents went to the jail in Alexandria but were not permitted to see their son. Accompanied by lawyer James Brosnahan, Walker's father Frank Lindh expressed disappointment after the jail visit.

"We're a little disappointed but the guards did tell us that John was in good health and we're very glad to hear that," Lindh said.

Brosnahan, who has complained that the government has denied Walker access to his family and his lawyers, said that he was not able to see his client.

He is one of at least four lawyers representing Walker, including Bill Cummings, a former U.S. Attorney fozzQI9istrict of Virginia and former federal prosecutors George Harris and Bill West.

Earlier on Wednesdzz 9%MMU`MQtement saying Walker was "comforted" to know his family had hired an attorney to represent him.

Brosnahan, hired by Frank Lindh and Marilyn Walker shortly after their son's capture in Afghanistan, said they had been given a letter from Walker on Wednesday in which he acknowledged they had found him legal representation.

U.S. Attorney General John Ashcroft has said Walker had repeatedly waived his rights to an attorney both verbally and in writing during interrogation sessions.

Walker was interrogated for about 45 days and most recently had been held aboard the U.S. warship Bataan in the Arabian Sea. He was taken to the warship from a prison outside the northern Afghan city of Mazar-i-Sharif, where an uprising occurred during which CIA agent Mike Spann was killed.

An FBI affidavit filed with the criminal complaint last week said Walker knew three months before the Sept. 11 attacks on America that bin Laden had sent people to the United States to carry out suicide missions.

The affidavit, based on interviews with Walker after his capture, said Walker stayed with al Qaeda despite knowing that bin Laden ordered the attacks that killed thousands of people.

Attorney General John Ashcroft said on Wednesday it was clear from Walker's own words that he chose to join forces with terrorists.

In announcing the charges against Walker last week, Ashcroft said charges of treason, which could bring the death penalty, would be difficult to prove but have not been ruled out. Ashcroft said on Wednesday the investigation of Walker continues.

The case has drawn attention in the United States as people debate whether Walker was a traitor.

Walker's parents have portrayed their son, who converted to Islam as a teen-ager, as a misguided idealist rather than a Muslim extremist. Nampa-Reuters